Search Results for author: Stephen J. Wright

Found 24 papers, 4 papers with code

Robust Second-Order Nonconvex Optimization and Its Application to Low Rank Matrix Sensing

no code implementations NeurIPS 2023 Shuyao Li, Yu Cheng, Ilias Diakonikolas, Jelena Diakonikolas, Rong Ge, Stephen J. Wright

We introduce a general framework for efficiently finding an approximate SOSP with \emph{dimension-independent} accuracy guarantees, using $\widetilde{O}({D^2}/{\epsilon})$ samples where $D$ is the ambient dimension and $\epsilon$ is the fraction of corrupted datapoints.

How to Make the Gradients Small Privately: Improved Rates for Differentially Private Non-Convex Optimization

no code implementations17 Feb 2024 Andrew Lowy, Jonathan Ullman, Stephen J. Wright

We use this framework to obtain improved, and sometimes optimal, rates for several classes of non-convex loss functions.

Extending the Reach of First-Order Algorithms for Nonconvex Min-Max Problems with Cohypomonotonicity

no code implementations7 Feb 2024 Ahmet Alacaoglu, Donghwan Kim, Stephen J. Wright

With a simple argument, we obtain optimal or best-known complexity guarantees with cohypomonotonicity or weak MVI conditions for $\rho < \frac{1}{L}$.

Complexity of Single Loop Algorithms for Nonlinear Programming with Stochastic Objective and Constraints

no code implementations1 Nov 2023 Ahmet Alacaoglu, Stephen J. Wright

To find a point that satisfies $\varepsilon$-approximate first-order conditions, we require $\widetilde{O}(\varepsilon^{-3})$ complexity in the first case, $\widetilde{O}(\varepsilon^{-4})$ in the second case, and $\widetilde{O}(\varepsilon^{-5})$ in the third case.

A randomized algorithm for nonconvex minimization with inexact evaluations and complexity guarantees

no code implementations28 Oct 2023 Shuyao Li, Stephen J. Wright

We consider minimization of a smooth nonconvex function with inexact oracle access to gradient and Hessian (without assuming access to the function value) to achieve approximate second-order optimality.

Accelerating optimization over the space of probability measures

no code implementations6 Oct 2023 Shi Chen, Qin Li, Oliver Tse, Stephen J. Wright

Most research has focused on optimization over Euclidean spaces, but given the need to optimize over spaces of probability measures in many machine learning problems, it is of interest to investigate accelerated gradient methods in this context too.

Correcting auto-differentiation in neural-ODE training

no code implementations3 Jun 2023 Yewei Xu, Shi Chen, Qin Li, Stephen J. Wright

Does the use of auto-differentiation yield reasonable updates to deep neural networks that represent neural ODEs?

Differentially Private Optimization for Smooth Nonconvex ERM

no code implementations9 Feb 2023 Changyu Gao, Stephen J. Wright

We develop simple differentially private optimization algorithms that move along directions of (expected) descent to find an approximate second-order solution for nonconvex ERM.

Cyclic Block Coordinate Descent With Variance Reduction for Composite Nonconvex Optimization

no code implementations9 Dec 2022 Xufeng Cai, Chaobing Song, Stephen J. Wright, Jelena Diakonikolas

Our convergence analysis is based on a gradient Lipschitz condition with respect to a Mahalanobis norm, inspired by a recent progress on cyclic block coordinate methods.

On the Complexity of a Practical Primal-Dual Coordinate Method

no code implementations19 Jan 2022 Ahmet Alacaoglu, Volkan Cevher, Stephen J. Wright

We prove complexity bounds for the primal-dual algorithm with random extrapolation and coordinate descent (PURE-CD), which has been shown to obtain good practical performance for solving convex-concave min-max problems with bilinear coupling.

Coordinate Linear Variance Reduction for Generalized Linear Programming

1 code implementation2 Nov 2021 Chaobing Song, Cheuk Yin Lin, Stephen J. Wright, Jelena Diakonikolas

\textsc{clvr} yields improved complexity results for (GLP) that depend on the max row norm of the linear constraint matrix in (GLP) rather than the spectral norm.

Variance Reduction via Primal-Dual Accelerated Dual Averaging for Nonsmooth Convex Finite-Sums

no code implementations26 Feb 2021 Chaobing Song, Stephen J. Wright, Jelena Diakonikolas

We study structured nonsmooth convex finite-sum optimization that appears widely in machine learning applications, including support vector machines and least absolute deviation.

Random Coordinate Underdamped Langevin Monte Carlo

no code implementations22 Oct 2020 Zhiyan Ding, Qin Li, Jianfeng Lu, Stephen J. Wright

We investigate the computational complexity of RC-ULMC and compare it with the classical ULMC for strongly log-concave probability distributions.

Random Coordinate Langevin Monte Carlo

no code implementations3 Oct 2020 Zhiyan Ding, Qin Li, Jianfeng Lu, Stephen J. Wright

We investigate the total complexity of RC-LMC and compare it with the classical LMC for log-concave probability distributions.

Adversarial Classification via Distributional Robustness with Wasserstein Ambiguity

no code implementations28 May 2020 Nam Ho-Nguyen, Stephen J. Wright

Inspired by this observation, we show that, for a certain class of distributions, the only stationary point of the regularized ramp loss minimization problem is the global minimizer.

Classification General Classification

Interleaved Composite Quantization for High-Dimensional Similarity Search

no code implementations18 Dec 2019 Soroosh Khoram, Stephen J. Wright, Jing Li

A method often used to reduce this computational cost is quantization of the vector space and location-based encoding of the dataset vectors.

Quantization Vocal Bursts Intensity Prediction

A Distributed Quasi-Newton Algorithm for Primal and Dual Regularized Empirical Risk Minimization

1 code implementation12 Dec 2019 Ching-pei Lee, Cong Han Lim, Stephen J. Wright

When applied to the distributed dual ERM problem, unlike state of the art that takes only the block-diagonal part of the Hessian, our approach is able to utilize global curvature information and is thus magnitudes faster.

Distributed Optimization

A Distributed Quasi-Newton Algorithm for Empirical Risk Minimization with Nonsmooth Regularization

1 code implementation4 Mar 2018 Ching-pei Lee, Cong Han Lim, Stephen J. Wright

Initial computational results on convex problems demonstrate that our method significantly improves on communication cost and running time over the current state-of-the-art methods.

Distributed Optimization

Training Set Debugging Using Trusted Items

no code implementations24 Jan 2018 Xuezhou Zhang, Xiaojin Zhu, Stephen J. Wright

The set of trusted items may not by itself be adequate for learning, so we propose an algorithm that uses these items to identify bugs in the training set and thus im- proves learning.

BIG-bench Machine Learning Bilevel Optimization

Online Algorithms for Factorization-Based Structure from Motion

no code implementations26 Sep 2013 Ryan Kennedy, Laura Balzano, Stephen J. Wright, Camillo J. Taylor

We present a family of online algorithms for real-time factorization-based structure from motion, leveraging a relationship between incremental singular value decomposition and recently proposed methods for online matrix completion.

Matrix Completion

On GROUSE and Incremental SVD

no code implementations21 Jul 2013 Laura Balzano, Stephen J. Wright

GROUSE (Grassmannian Rank-One Update Subspace Estimation) is an incremental algorithm for identifying a subspace of Rn from a sequence of vectors in this subspace, where only a subset of components of each vector is revealed at each iteration.

Robust Dequantized Compressive Sensing

no code implementations3 Jul 2012 Ji Liu, Stephen J. Wright

We consider the reconstruction problem in compressed sensing in which the observations are recorded in a finite number of bits.

Compressive Sensing Quantization

HOGWILD!: A Lock-Free Approach to Parallelizing Stochastic Gradient Descent

5 code implementations28 Jun 2011 Feng Niu, Benjamin Recht, Christopher Re, Stephen J. Wright

Stochastic Gradient Descent (SGD) is a popular algorithm that can achieve state-of-the-art performance on a variety of machine learning tasks.

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